Spiral muffler



Nov. 6, 1962 M. E. PIGMAN 3,062,317

SPIRAL MUFFLER Filed Dec. 16, 1957 z Sheets-Sheet 1 FIG.1

M. E. PIGMAN INVENTOR.

ATTORNEYS Nov. 6, 1962 M. E. PIGMAN 3,062,317

SPIRAL MUFFLER Filed Dec. 16, 1957 2 Sheets-Sheet 2 M. E PIG MAN INVENTOR.

ATTORNEYS United States Patent Ori ice 3,062,317 Patented Nov. 6, 1962 Delaware Filed Dec. 16, 1957, Ser. No. 703,069 2 Claims. (Cl. 181-66) This invention relates to an improved muffier of the spiral type which can be used with internal combustion engines and/or devices where absorption of sound vibrations of a gaseous medium is required. The object of this invention, therefore, is to provide an efiicient muffler device readily adaptable to mass production techniques, easily manufactured and assembled at a minimum cost, compactly arranged to take up a minimum of space and functionally dependable. These and other objects will become more apparent when the above mentioned embodiment is described in more detail which description will be aided by drawings in which:

FIGURE 1 is a plan elevational view of a muffier made in accordance with the applicants invention and showing a flow path through the muffier;

FIGURE 2 is a cross sectional view of the muffier taken on the plane indicated by the lines 22 of FIGURE 1;

FIGURE 3 is an end view of the muffler construction shown in FIGURE 1 and looking at the construction from the intake side;

FIGURE 4 is a perspective view of the inlet baflie;

FIGURE 5 is an enlarged fragmentary view of the spiral wall and showing the apertures contained therein; and

FIGURE 6 is a sectional view taken on the plane indicated as 6-6 of FIGURE 5.

Referring now to the drawings, and particularly FIG- URE 1, reference numeral 10 indicates a muffier body of a generally flat circular construction and having an inlet pipe 11 and an exhaust pipe 12. Mufiler body 10 is a compact construction which is relatively low in height and small in configuration. The gaseous medium is received from the source of the sound vibrations through the intake pipe 13 (shown in part) and is exhausted through tail pipe 14 (also shown in part) coaxially aligned with the exhaust pipe 12. Mufiier body 10 is composed of an outer shell 16, consisting of a deep drawn outer shell top 17 and a relatively shallow outer shell bottom 18, and an inner shell 19, consisting of a deep drawn inner shell top 21 and a relatively shallow inner shell bottom 22. The inner and outer shell sections are joined at their radial flanges 23 as by seam welding.

An intake opening 24 is provided in the inner and outer top shell sections 17 and 21 through which the inlet pipe 11 extends and is secured.

In FIGURE 2, it can be seen that the outer shell top 17 is bulged outwardly at 26 and the inner shell top 21 is depressed in the same plane to form a ramp-like trough 27. The exhaust pipe 12 is located and secured in the enlarged opening 28 located in the outer top shell 17 and extends a short distance into the area between the bulge 26 and the trough 27. Both the bulge 26 and the trough 27 extend from the opening 28 adjacent to the outer periphery of the muffler body to the approximately center of the mufiler body. An exhaust port 38 is located in the upper part of the trough 27 in the apex area. Exhaust gases are exhausted from the interior of the muffler through this port.

The interior of the muffler body is partitioned to provide a spiral fiow path for the gaseous medium as indicated by the broken arrows 29. This flow path is divided into an inlet section 31 and an outlet section 32, and is in the form of a flat spiral, the beginning of the spiral path being on the outside and the end of the spiral path being on the center of the spiral path. The inlet section 31 is located on the intake side of the trough 27, while the exhaust section 32 is located on the exhaust side of the trough 27. An inner wall 33 is anchored to the inner shell 19 on the exhaust section of the spiral path by welding tabs 34 and twist tabs 36 and is circularly formed to continue the flow path which ends near the center of the mufller body. In FIGURE 5, the attachment means 34 and 36 are shown as well as the plurality of apertures 37 for the passage of the gaseous medium. As stated before, the inner wall 33 extends to the trough 27 and exhaust gases are exhausted through the port 38 and through the exhaust pipe 12. In its initial spiraling movement, the wall 33 is notched to fit under the trough 27.

Provisions for bafiling the spiral path are provided in the form of inlet and exhaust bafile members 39 and 41 respectively, which are secured in the inlet and exhaust passages 31 and 32 respectively. Inlet baffle 39 is secured to the inner shell 19 in the inlet passage 31 while the exhaust baffle 41 is secured to the inner shell 19 and inner wall 33 respectively in the exhaust passage 32. The bafiles are similar in that they are provided with a plurality of ridges 42' having a front acutely angled face 43 and a sloping rear face 44. Ridges 42 are joined together by land sections 45. The baflies are joined by their respective land sections to the inner shell and inner wall. Like the inner wall 33, the ridges are provided with a plurality of apertures 46 which permit the passage of sound waves to go through the ridges and be reflected into the incoming sound Waves. Although shown as having ridges of an equal height and shape, these ridges may be varied to give different sound reflection and absorption qualities. It is, of course, possible to vary the size of the inner wall and ridge apertures 37 and 46 to obtain the best mufiiing arrangement.

Dependent upon the positioning of the mufiler, it is possible to provide drain holes such as at 47 if the mufiler is positioned in the horizontal plane or at 48 if the mufiier if vertically disposed. It is also possible to further mufifie the sound waves by the installation of sound absorbing material such as steel wool, glass wool, asbestos fiber or the like, placed in the space 49 beneath the ridges.

It is to be understood as well that the fiow path outside of the baffies is straight through and that the area beneath the lower portion of the trough 27 is equal in space to the straight-through path section thus reducing mufiler back pressure to a minimum.

It will be understood that the invention is not to be limited to the exact construction shown and described, but that various changes and modifications may be made without departing from the spirit and scope of the invention, as defined in the appended claims.

What is claimed is:

1. In a spiral mulfier for engine exhaust gases, a housing having lower, intermediate and upper walls dividing said housing into first and second chambers, said housing having an inlet opening communicating with said first chamber and an outlet opening communicating with said second chamber, a pair of continuous baffies mounted within said first chamber between said lower and intermediate housing walls and forming with said lower and intermediate walls a generally spiral conduit communicating at one end with said inlet opening, said intermediate housing wall having an enlarged opening providing communication between the opposite end of said spiral conduit and said second chamber, the baffle forming one side wall of one said spiral conduit having a curved surface of generally spiral configuration, and the baffle forming the other side wall of said spiral conduit having a continuous surface of generally undulating configuration.

2. The structure defined by claim 1 which is further characterized in that said upper and intermediate housing walls are closely spaced with respect to each other throughout the major portion of their areas to form a shallow chamber portion, said upper and intermediate housing walls being spaced apart a substantially greater distance adjacent said outlet opening and the opening in said intermediate wall to provide an enlarged portion in said second chamber establishing communication between the inner end of said spiral conduit and said outlet opening.

References Cited in the file of this patent UNITED STATES PATENTS Mock June 22, 1915 Murphy Jan. 22, 1924 Jehle Feb. 7, 1928 FOREIGN PATENTS Sweden J an. 2, 21940 

